According to the state of the art, a controller is necessary to use an analyzer such as a liquid chromatograph (LC), which is controlled in one of the following methods.                An independent control unit equipped with firmware (or built-in) programs is prepared, and is connected to the LC with a communication cable.        Appropriate LC controlling programs are installed in a general-purpose computer such as a personal computer, which constitutes an LC controller, and the computer is connected to the LC with a communication cable.        
An independent control unit is expensive due to the high cost of manufacture. And the control programs installed as firmware in the control units, in general, differ from one type of analyzer to another. When, therefore, the firmware programs are to be newly developed or to be modified, detailed information specific to that type of analyzer is necessary, which is burdensome to the program developers.
In the case of installing controlling programs in a general-purpose computer, the programs normally include, besides those for controlling the LC analyzer, a group of programs for analyzing and processing data obtained through measurements. This means that the controlling programs as a whole become quite versatile and very big, so that the development and modification of the programs also require a lot of time and cost.
From the users' point of view, a certain level of knowledge or experience is needed to master such versatile programs, and the acquisition of such knowledge or experience takes a lot of time. On the other hand, many users actually use the programs only for formulaic tasks, such as monitoring the operation of the analyzer. For such tasks, it will be more convenient to use one simple program rather than several versatile programs. In this sense, conventional controlling programs need reconsidering.
Independent control units have no such problem. But the user must go to the control unit when the user wants to monitor the operation of the analyzer or set/reset the analyzing conditions, which requires additional time. Many types of analyzers have been proposed so far which are equipped with a controller enabling the user to monitor the operation of the analyzer from a remote place. The Japanese Unexamined Patent Publication No. 2000-283935 discloses one such analyzer. But until now there has never been an analyzer that allows the user to set/reset the analyzing condition from a remote place.